Telecine device that utilizes standard video camera circuits

ABSTRACT

A telecine device that replays such movie films as 8 millimeter, 16 millimeter and 35 millimeter format film, automates interpolation of the different frame rates between film and video signals by comparing film pulses with video signal pulses and controlling a stepping motor to advance the frames, and utilizes standard video camera circuits to output the images into analog video signals or digital video signals in a variety of formats.

CROSS-REFERENCE TO RELATED APPLICATIONS

Japan Patent Application (Published) 2005-252418

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO MATERIAL SUBMITTED SEPARATELY

Not Applicable

BACKGROUND OF THE INVENTION

Cinema projectors for certain film formats, particularly 8 millimeter film, have not been manufactured since the 1980s. To date, the only options for replaying 8 millimeter film were to use projectors that had had more than 20 years pass since their manufacture or to pay a fee to a video conversion service to convert the film to a video or DVD format. Cinema projectors that are more than 20 years old tend to be aged and decrepit, most are likely to suffer from some malfunction and official support from the most manufacturers is no longer available. In short, even if a member of the general public possesses the film, they do not have any means of projecting the film when their projector breaks down. Moreover, only high-priced commercial telecine equipment is available for converting the film into the video signal format, making it difficult to obtain substitute equipment for the film projectors. Furthermore, none of the recording frame rates for film—there are various formats at 16, 18 or 24 frames per second-correspond to the frame rates for video signals (the NTSC format is 30 frames per second, the PAL and SECAM are 25 frames per second), making it useless to simply replace one film frame with one or two video signal frames.

Many formats that interpolate the difference between the film recording frame rate and video signal frame rates, many conversion formats and many telecine devices have been invented, but most of them are of a format that advances the film at fixed speeds and interpolates at the conversion to the video signal stage, and are made for commercial films that are larger in size than the 16 millimeter film recorded at 24 frames per second. For example, Japan patent applications 2002-359775, 2002-77832 and 2001-103373 all use these methods. The 8 millimeter film-Video Conversion Device filed under Japan patent application 2005-252418 by the inventor of the current application provides for a telecine device that is smaller and cheaper than the commercial telecine devices, but it advances the film at a fixed speed and is no different from the devices that interpolate at the conversion to video signal stage. Thus, the processes that interpolate at the stage when the images are converted to a video signal cannot use standard video camera circuits without modification, making it necessary to develop specialized circuits and low-cost production is therefore limited. If the interpolation can be conducted when the film is being advanced and not during video signal conversion, standard video camera circuits can be used without modification to convert to video signals and can be expected to further lower the cost of the device.

Methods of converting the film images to video signals by controlling the film frame advancement have been proposed in such patent applications as Japan patent Heisei-11-32255 and Heisei-10-126685, and they propose to raise image quality by synchronizing the film frame advancement with the video signal creation, but they do not play the film in real time and do not automatically interpolate the difference between the film recording frame rate and the video signal frame rate. Namely, they are not intended to create video signals from movie and other film in real time. To date, there has been no telecine device using the method of interpolating the difference between recording frame rates and video signal frame rates at the film frame advancement stage, and using standard video camera circuits without modification to convert to a video signal.

BRIEF SUMMARY OF THE INVENTION

[Purpose]

By automatically interpolating the difference in playback frame rates between the film recording frame rate and the video signal frame rate, the invention purposes to use standard video camera circuits to convert the images into flicker-free video signals. It also purposes the film images to be viewed on a television, recorded onto such media as video tapes or DVDs, or downloaded onto a computer.

[Method]

By comparing the replay speed of a movie film such as 8 millimeter, 16 millimeter, 35 millimeter movie film (film replay pulse) with the video frame signal (video frame pulse) or the video field signal (video field pulse), it generates a pulse (hereafter called the stepping motor control pulse) and uses the stepping motor control pulse to control a stepping motor to advance the frames at the right speed, and automatically interpolates the difference in frame rates (frames per second) and replays in real time. Then utilizes standard video camera circuits to output the film images into analog video signals or digital video signals. By allowing for the adjustment of the film drive mechanisms and the dimensions of the optical components as well as the control programs, it is easily able to produce telecine device that support multiple film formats.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

Diagram 1: Overall Schematic

-   (1) Film -   (2) Reel A -   (3) Reel B -   (4) Film Rewinding Motor -   (5) Film Take-up Motor -   (6) Stepping Motor -   (7) Tension Roller -   (8) Tension Roller -   (9) Light Source -   (10) Video Camera Unit -   (11) Film Speed Detection Roller -   (12) Magnetic Head for Audio Replay -   (13) Guide Rollers -   (14) Video Signal Conversion Unit -   (15) Audio Circuit Unit -   (16) Output Terminal Unit -   (17) Pulse Controller Unit -   (18) Film Replay Speed Settings Buttons -   (19) Synchronized Pulse -   (20) Film Replay Pulse -   (21) Video Frame Pulse -   (22) Stepping Motor Control Pulse -   (23) Video Field Pulse

[Diagram 2]

Interpolation Timing by Frame

-   (19) Synchronized Pulse (1 per second) -   (20) Film Replay Pulse ( 1/18 second) -   (21) Video Frame Pulse ( 1/30 second) -   (22) Stepping Motor Control Pulse     Interpolation Timing by Field -   (20) Film Replay Pulse ( 1/18 second) -   (23) Video Field Pulse ( 1/60 second) -   (22) Stepping Motor Control Pulse

[Diagram 3]

Interpolation Timing by Frame

-   (19) Synchronized Pulse (1 per second) -   (20) Film Replay Pulse ( 1/24 second) -   (21) Video Frame Pulse ( 1/30 second) -   (22) Stepping Motor Control Pulse     Interpolation Timing by Field -   (20) Film Replay Pulse ( 1/24 second) -   (23) Video Field Pulse ( 1/60 second) -   (22) Stepping Motor Control Pulse

DETAILED DESCRIPTION OF THE INVENTION

As shown in Diagram 1, the film (1) is fed from Reel A (2) and taken up by Reel B. (3). A motor (4) for winding the film (4) is located at Reel A (2) and a motor for reeling in film at Reel B (3). A stepping motor (6) that advances the film is located between Reel A (2) and Reel B (3). Tension rollers (7, 8) absorb the shock as the film pulses as it is advanced. It is also equipped with a light source (9), a video camera unit (10), a film speed detection roller (11), a magnetic head for audio replay (12) and guide rollers (13). The accompanying electronic circuits comprise a video camera unit (10), a video signal conversion unit (14), an audio circuit unit (15), an output terminal unit (16) and a pulse controller unit (17).

When replay of the film is initiated, a motor control signal from the pulse controller unit (17) causes the motor (5) at Reel B (3) to turn and reel in the film, and the stepping motor control pulse (22) causes the stepping motor (6) to advance the film frames. The film (1) images are reproduced by the light from the light source (9) and the video camera unit (10) records it in synchronization with the timing of the film frame advancement. The signal is then passed through the video signal conversion unit (14) and is transformed into video images.

The film playback speed is controlled by the film replay pulse (20), which is generated by the pulse controller unit (17) and is controlled by the setting of the film replay speed settings buttons (18). This pulse is used as the basis to generate the motor control signal and the stepping motor control pulse (22), and controls the movement of the motor (5) at Reel B (3) and the stepping motor (6). Although the film frames are advanced by the stepping motor control pulse (22) between the tension roller (7) on the Reel A (2) side and the tension roller on the Reel B (3) side, after the film passes over the tension roller (8) on the Reel B (3) side the speed is controlled by the film speed detection roller (11), which controls the Reel B (3) motor (5) in order to maintain an even speed for stable audio playback without pulsation.

In the case of the NTSC video format, the stepping motor control pulse (22) is generated by the following method by the film replay pulse (20) in the pulse controller unit (17) and the video frame pulse (21) at 1/30-second intervals or the video field pulse (23) at 1/60-second intervals (See Diagram 2). When image interpolation is conducted in frame-by-frame increments, the stepping motor control pulse (22) is based on the film replay pulse (20) and is generated when the video frame pulse (21) coincides with the film replay pulse (20). When they do not coincide, the device searches for the video frame pulse (21) immediately following the last film replay pulse (20) and initiates the stepping motor control pulse (22). For example, when the film replay speed is 18 frames per second (film replay pulse is 1/18 of a second), the intervals between stepping motor control pulses (22) become 1/15, 1/15, 1/30 second, a pattern which is repeated. In other words, among the video frame pulses (21), pulses number 2, 4, 5, 7, 9, 10, 12, 14, 15, 17, 19, 20, 22, 24, 25, 27, 29, 30 trigger the stepping motor control pulses (22). And a pattern of 2 frames, 2 frames, 1 frame is repeated to convert the film images to video signals.

If the interpolation is performed using field increments (progressive format), the stepping motor control pulse (22) is generated when the film replay pulse (20) (the basis for the pulse) coincides with the video field pulse (23). When they do not coincide, the device searches for the video field pulse (23) immediately following the last film replay pulse (20) and initiates the stepping motor control pulse (22). For example, when the film replay speed is 18 frames per second (film replay pulse is 1/18 of a second), the intervals between stepping motor control pulses (22) become 1/15, 1/20and 1/20 second, a pattern which is repeated. In other words, among the video field pulses (21), pulses number 4, 7, 10, 14, 17, 20, 24, 27, 30, 34, 37, 40, 44, 47, 50, 54, 57, 60 trigger the stepping motor control pulses (22). And a pattern of 4 fields, 3 fields, and 3 fields is repeated to convert the film images to video signals.

Since the film replay pulse (20), video frame pulse (21) and video field pulse (23) and stepping motor control pulse (22) are all generated using the same clock in the pulse controller unit, the film frame advancement timing and the video camera unit shutter timing are correctly matched. However, to prevent the images from being captured as video signals while the film is in motion (during frame advancement), an LED capable of flashing at high speed is used as the light source (9). It is synchronized with the stepping motor control pulse (22) or the video frame pulse (21) or the video field pulse (23), and is only extinguished for the time required to advance the film frames. The period over which the light source (9) is extinguished is determined by the characteristics of the LED and the stepping motor specifications. The shutter timing for the video camera unit (10) is also adjusted to obtain optimal video signal quality. The shutter timing is determined by the amount of light produced by the light source (9) and the specifications of the circuits used in the video camera unit (10) and the video sign conversion unit (14).

The device uses the same principle to automatically generate the stepping motor control pulses (22) for film replay speeds that are higher than 18 frames per second. (See Diagram 3). Similarly, the stepping motor control pulses (22) can be automatically generated using this same principle to handle the 25 frame video signals of the PAL and SECAM video formats. 

1. A telecine device that replays a movie film, such as an 8 millimeter film, 16 millimeter film or 35 millimeter film, automatically interpolating the difference in the number of images played each second between film and video signals by comparing the replay speed of a film (film replay pulse) with the video frame signal (video frame pulse) or the video field signal (video field pulse) and controlling a stepping motor with the generated pulse to advance frames, and utilizes standard video camera circuits to output the film images into analog video signals or digital video signals. 